How objects fly
Have you ever been in a plane and wondered how it was flying? Or seen a bug flying over you? Well I have an explanation to describe that.
There are four forces that allow the plane to fly. Lift is a force that moves the plane up and works against weight. Thrust is a force that moves the plane forward and works against drag. Weight is a force that pulls the plane down and works against lift. Drag is a force that slows the the plane down and works against thrust.
The four forces
Lift occurs when the flow of a moving gas (air) is turned by a solid object. For a plane or bird to take off there must be a stronger lift force than weight. Lift also occurs when the air flows under the wing.
Drag acts in a direction that is opposite to the direction of the plane or bird. Drag slows the plane or bird down. Drag is important when the plane or bird is landing because the plane or bird uses drag to slow down ready to hit the ground for landing.
A plane or birds weight is always directed to the centre of the earth. Weight is very important when a plane or bird is landing because the weight of the plane or bird will pull the plane or bird down to earth.
Thrust is the force which moves the plane or bird though the air. Thrust must overcome drag or else the plane or bird will not move through the air. In a plane thrust is created by the engines. In birds the thrust is created by muscles.
How things fly?
For a plane or bird to take off their must be a strong lift and thrust force because they work together to lift the plane off the ground. For a plane or bird to land the forces drag and weight need to be the strongest to slow the object down and pull it down to the ground. When a plane or bird is in the air there must be an equal weight and lift force to hold the plane or bird in the air. For the object to turn the air flow must become unequal to turn the object.
So overall a plane needs the four forces to fly. It has became obvious that humans cannot fly because gravity is too strong and we do not have enough lift and thrust to get off the ground. So now I hope when you see a plane or bird fly over you know how it is flying.